Re: Java puzzler

On 5/12/2011 6:18 PM, Patricia Shanahan wrote:


What I envision is only to only add the deciding in the compiler, not at
run time.

I'm not talking about setting a mode per thread or application. I only
want to affect what byte codes get generated at compile time.
Everything already compiled or compiled with existing options retains
its current semantics.

For example, if I do something like this

   public int encryptAndCount( byte[] buffer ) {
     @strictint // assume this turns on overflow checking
     int i = 0;
     int count = 0;
     while( buffer[i] != 0 ) { // assume null terminated
       count++;
       encrypt( buffer, i );
     }
     return count;
   }

and encrypt is something like this:

public class Encrypt {
   private static byte rand;
   public static void encrypt( byte[] buffer, int i offset ) {
      rand += 42; // world's worst encryption
      buffer[offset] ^= rand;
   }
}

the method encryptAndCount has overflow detection, but that does not
"flow into" the method encrypt. They are distinct compilation units,
and in this case I immagine that "@strictint" only applies to one method
at a time anyway. So it all depends on the byte codes, not threads or
program flow, and doesn't happen dynamically at run time.